4.7 quake shakes Southern California, rattling nerves [Updated]

The temblor hit about 8:40 p.m. 3 miles from the South Bay community of Lennox. A 3.1 aftershock occurred a few minutes later.

The temblor started about 8.4 miles below the surface, according to the U.S. Geological Survey. Residents in the Lennox area said dishes fell off shelves, but there were no reports of serious damage.

It's unclear what fault the quake struck on. The Newport-Inglewood fault, which has produced several powerful temblors, runs through that general area.

An initial assessment by the Los Angeles Fire Department found "no major structural damage, no serious injuries," according to spokesman Brian Humphrey's Twitter feed.

At the Los Angeles County Sheriff's Department's Lennox station, deputies said the shaking was brief but intense. "It was pretty strong but over in about 10 seconds," said Lt. Kent Wegener. "There are no [immediate] reports of damage. At this point, we are checking all the critical facilities and getting our ducks in a row."

Los Angeles County fire officials also said they had not received damage reports in residential or industrial areas, including the coastal refineries.

KCAL-TV Channel 9 interviewed moviegoers at a shopping mall in Redondo Beach who said the quake shook the screen and caused some ceiling tiles to fall. But firefighters said there was no serious damage or injuries. KCAL also reported numerous burglar alarms going off and some people being cut by broken glass.

In Hawthorne, firefighters were called to Chadron Avenue, near Crenshaw Boulevard, where a light pole was damaged during the earthquake. One man also suffered a heart attack, but it was unclear whether that was connected to the quake. “Luckily, nothing major so far,” said Hawthorne Police Lt. Michael Ishii.

Some residents said they were having trouble with cellphone service, but it's unclear how widespread the problems are.

The earthquake was “a bit deep,” said U.S. Geological Survey seismologist Susan Hough – originating 8.4 miles below the surface. “That tends to make it less sharp – less of a jerky, abrupt motion,” Hough said. As a result, most of the region felt the quake as a rolling motion, though some closer to the center may have felt a jolt.

Lucy Jones, seismologist at the U.S. Geological Survey, said the earthquake appears to be consistent with a rupture on the Newport-Inglewood fault. She said the quake was too small to break the surface, so they can't definitively identify faults. Jones said this fault isn't typically thought to be capable of producing a large quake, like the San Andreas fault is known to do. But it was responsible for the 1933 Long Beach earthquake, which measured about 6.3 in magnitude. The Long Beach quake is about as big as seismologists expect from this fault, she said.

"There have been numerous magnitude 3s on it over the years, a cluster of them in the 1980s," she said. "In general, it's an active area."

The quake was initially logged as a magnitude 5 by automatic sensors, but as more data came in, seismologists downgraded it to a magnitude 4.7. It also had an aftershock with a magnitude of 3.1 about six minutes later. So far, Jones said, 12,000 people have reported feeling the shaking, including some in San Diego. She was not surprised at the number of people reporting, as the quake shook a densely inhabited area.

Nothing about the quake or its aftershocks looked unusual, she said. "It’s a real garden-variety California earthquake so far."

What’s notable about it is location with respect to people.

She said the most similar earthquake to this one was a temblor that shook the Inglewood area in 1920. That was classified as a "minor damaging shock."

Updated at 10:30 p.m.: "County fire dispatchers reported no damage at area refineries although units had responded to numerous alarms triggered by the quake," said Los Angeles County Fire Inspector Frank Garrado. "We have had some alarm activations but the [fire units] have reported false alarms [there]."

Disneyland temporarily closed rides when the quake occurred, but no problems were reported.

Updated at 11:05 p.m.: Plate-glass windows shattered at two businesses on South Street in Long Beach. The Daily Breeze posted photos showing bottles of wine and other grocery items scattered on the floor of an Albertson's store in Redondo Beach.

Updated at 11:35 p.m.: According to City News Service, the Chevron refinery in El Segundo had a "burnoff,'' in which excess refinery gases were burned. Police said burnoffs are standard procedure after an earthquake.

Photos: Employees of a Starbucks at Hawthorne and Artesia Boulevards in Torrance clean up glass that fell from a window above, reportedly injuring one person who was taken to a nearby hospital. Credit: Jay L. Clendenin / Los Angeles Times